Investigation of a Simple Pickup Method for Doping Molecules into Water Clusters

A capillary pickup method was investigated for doping molecules into water clusters, which were produced by supersonic expansion, and underwent a sticking collision with a crossed beam from the capillary. This method was applied to H₂O clusters in a beam with pickup of DCl, CH₃OH, NH₃, CO₂ and D₂O molecules, however, we found only molecule of DCl can be picked up by water clusters with the capillary configuration in those tested dopants. Meanwhile, two different distances between the capillary to the nozzle were investigated based on the collected mass spectra, and we found that the smaller distance can obtain the stronger mixed cluster intensity.